Rust fungi gain their nutrients from living cells. This requires a specialized penetration of the fungi into a living plant cell called a haustoria. This develops from a haustorial mother cell. The plant cell membrane surrounds the main haustorial body. An iron- and phosphorus-rich neck band bridges the plant and fungal membranes and acts as a seal preventing the escape of nutrients into the plant. The rust fungi will then continue to grow and invade the plant until it is ready to make new spores.
